Spacers for insulated glass units

ABSTRACT

This disclosure provides spacers for smart windows. In one aspect, a window assembly includes a first substantially transparent substrate having an optically switchable device on a surface of the first substrate. The optically switchable device includes electrodes. A first electrode of the electrodes has a length about the length of a side of the optically switchable device. The window assembly further includes a second substantially transparent substrate a metal spacer between the first and the second substrates. The metal spacer has a substantially rectangular cross section, with one side of the metal spacer including a recess configured to accommodate the length of the first electrode such that there is no contact between the first electrode and the metal spacer. A primary seal material bonds the first substrate to the metal spacer and bonds the second substrate to the metal spacer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/312,057, filed Dec. 6, 2011, by Bhatnagar et al., which applicationclaims benefit under 35 U.S.C. §119(e) to U.S. Provisional PatentApplication No. 61/421,154, filed Dec. 8, 2010, and to U.S. ProvisionalPatent Application No. 61/435,914, filed Jan. 25, 2011, all of whichapplications are herein incorporated by reference.

FIELD

The disclosed embodiments relate generally to spacers and insulatedglass units containing them, and more particularly to insulated glassunits including optically switchable devices.

BACKGROUND

Various optically switchable devices are available for controllingtinting, reflectivity, etc., of window panes or lites. Electrochromicdevices are one example of optically switchable devices. Electrochromismis a phenomenon in which a material exhibits a reversibleelectrochemically-mediated change in an optical property when placed ina different electronic state, typically by being subjected to a voltagechange. The optical property being manipulated is typically one or moreof color, transmittance, absorbance, and reflectance. One well knownelectrochromic material is tungsten oxide (WO₃). Tungsten oxide is acathodic electrochromic material in which a coloration transition,transparent to blue, occurs by electrochemical reduction.

Electrochromic materials may be incorporated into, for example, windowsfor home, commercial, and other uses. The color, transmittance,absorbance, and/or reflectance of such windows may be changed byinducing a change in the electrochromic material; i.e., electrochromicwindows are windows that can be darkened or lightened electronically. Asmall voltage applied to an electrochromic device of the window willcause it to darken; reversing the voltage causes it to lighten. Thiscapability allows for control of the amount of light that passes throughthe window, and presents an enormous opportunity for electrochromicwindows to be used not only for aesthetic purposes but also forsignificant energy-savings. With energy conservation being foremost inmodern energy policy, it is expected that growth of the electrochromicwindow industry will be robust in the coming years.

SUMMARY

Spacers for insulated glass units (IGUs) incorporating electrochromicwindows are disclosed herein. The IGUs disclosed herein generallyinclude measures for avoiding electrical shorting between a metal spacerand conductive components of the electrochromic window, such as busbars, wires, and associated electrical connections.

In one embodiment, a window assembly includes a first substantiallytransparent substrate having an optically switchable device disposed ona surface of the first substantially transparent substrate. Theoptically switchable device includes electrodes. A first electrode ofthe electrodes has a length about the length of a side of the opticallyswitchable device (e.g., the optically switchable device may berectangular). The window assembly further includes a secondsubstantially transparent substrate and a metal spacer between the firstand the second substantially transparent substrates. The metal spacerhas a substantially rectangular cross section, with one side of themetal spacer including a recess configured to accommodate the length ofthe first electrode such that there is no contact between the firstelectrode and the metal spacer. A primary seal material bonds the firstsubstantially transparent substrate to the metal spacer and bonds thesecond substantially transparent substrate to the metal spacer.

In another embodiment, a window assembly includes a first substantiallytransparent substrate having an optically switchable device disposed ona surface of the first substantially transparent substrate. Theoptically switchable device includes electrodes. A first electrode ofthe electrodes has a length about the length of a side of the opticallyswitchable device. The window assembly further includes a secondsubstantially transparent substrate and a metal spacer between the firstand the second substantially transparent substrates. The metal spacerhas a substantially rectangular cross section, with at least oneexternal face of the metal spacer being coated with an electricallyinsulating coating that prevents electrical communication between themetal spacer and the first electrode. A primary seal material bonds thefirst substantially transparent substrate to the metal spacer and bondsthe second substantially transparent substrate to the metal spacer.

In another embodiment, a window assembly includes a first substantiallytransparent substrate having an optically switchable device disposed ona surface of the first substantially transparent substrate. Theoptically switchable device includes electrodes. A first electrode ofthe electrodes includes a lead. The window assembly further includes asecond substantially transparent substrate and a metal spacer betweenthe first and the second substantially transparent substrates. A primaryseal material bonds the first substantially transparent substrate to themetal spacer and bonds the second substantially transparent substrate tothe metal spacer. The metal spacer and the primary seal material form abarrier between an exterior region of the window assembly and aninterior region of the window assembly. A connector key joins with orotherwise connects two ends of the metal spacer, with the lead passingfrom the first electrode, under the connector key, and into the exteriorregion of the window assembly. The connector key is not in electricalcommunication with the lead.

In another embodiment, a window assembly includes a first substantiallytransparent substrate having an optically switchable device disposed ona surface of the first substantially transparent substrate. Theoptically switchable device includes electrodes. A first electrode ofthe electrodes has a length about the length of a side of the opticallyswitchable device. The window assembly further includes a secondsubstantially transparent substrate and a spacer between the first andthe second substantially transparent substrates. The spacer includes ametal portion having a substantially rectangular hollow cross sectionand an electrically non-conductive portion having a substantiallyrectangular cross section. One side of the rectangular cross section ofthe electrically non-conductive portion includes a recess that forms achannel along the one side that accommodates the length of the firstelectrode. A primary seal material bonds the first substantiallytransparent substrate to the spacer and bonds the second substantiallytransparent substrate to the spacer.

In another embodiment, a window assembly includes a first substantiallytransparent substrate having an optically switchable device disposed ona surface of the first substantially transparent substrate. Theoptically switchable device includes electrodes. A first electrode ofthe electrodes has a length about the length of a side of the opticallyswitchable device. The window assembly further includes a secondsubstantially transparent substrate and a metal spacer between the firstand the second substantially transparent substrates. The metal spacerhas a substantially rectangular cross section. A first primary sealmaterial bonds the first substantially transparent substrate to themetal spacer. The first primary seal material includes electricallynon-conductive particles that define a spacing between the firstsubstantially transparent substrate and the metal spacer and preventcontact between the metal spacer and the first electrode. A secondprimary seal material bonds the second substantially transparentsubstrate to the metal spacer.

These and other features and advantages will be described in furtherdetail below, with reference to the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C show examples of schematic diagrams of electrochromicdevices formed on windows.

FIGS. 2A and 2B show cross-sectional schematic diagrams of theelectrochromic window as described in relation to FIGS. 1A-C integratedinto an IGU.

FIG. 3A depicts an example of an electrochromic window fabricationprocess.

FIG. 3B depicts an example of a window assembly.

FIG. 4 shows examples of three modes of potential shorting to the spacerand consequent failure of an electrochromic device in an IGU.

FIG. 5A shows an example of a cross-section of an edge region of an IGUwhere the spacer of the IGU and the bus bar reside.

FIG. 5B shows examples of different implementations of bus bars.

FIG. 5C shows cross-sections of other spacers in accord with embodimentsdescribed herein.

FIG. 6 shows two embodiments of connector keys.

FIG. 7 shows an example of a detailed cross-sectional view of a crimpedconnector key aligned on a glass sheet with an electrochromic devicefabricated thereon.

FIG. 8 shows an example of a cross-sectional illustration of a spacerwhich has a notch on the bottom to accommodate the full length of thebus bar.

FIG. 9 shows an example of a cross-sectional illustration of a spacer inwhich the primary seal material (e.g., PIB) is modified to resistcompression.

FIG. 10 shows an example of a cross-sectional illustration of a spacerin which the spacer itself is modified so that one of its four walls ismade of an electrically non-conductive or insulating material.

FIGS. 11A-11C show examples of diagrams of an IGU with a two-partspacer.

DETAILED DESCRIPTION

It should be understood that while the disclosed embodiments focus onelectrochromic (EC) windows (also referred to as smart windows), theconcepts disclosed herein may apply to other types of switchable opticaldevices, including liquid crystal devices, suspended particle devices,and the like. For example, a liquid crystal device or a suspendedparticle device, instead of an electrochromic device, could beincorporated in any of the disclosed embodiments.

An insulated glass unit (IGU) is part of the transparent component of awindow. In the following description, an IGU may include twosubstantially transparent substrates, for example, two glass lites,where at least one lite includes an electrochromic device disposedthereon, and the lites have a spacer disposed between them. One or moreof the lites may itself be a laminate structure of lites. An IGU istypically hermetically sealed, having an interior region that isisolated from an exterior region including the ambient environment.

Disclosed herein are various embodiments in which electrochromic windowsare incorporated in IGUs with spacers having improved configurations. Anelectrochromic window includes a transparent substrate (e.g., a glasssheet or lite) on which is provided a thin electrochromic device. Metalspacers conventionally employed in IGUs may not work well withelectrochromic windows due to, e.g., shorting issues with the electricalcomponents of the electrochromic device on one or more lites of thewindow unit. Specifically, the IGUs disclosed herein generally havemeasures for avoiding electrical shorting between a metal spacer andconductive components of the electrochromic window, such as bus bars,for example.

For example, electrochromic devices on glass lites use conductive wires,bus bars, or other connections that pass a spacer used to form an IGU,for electrical communication to the electrochromic device. Spacers areoften chosen, or required, to be a metal, and for some IGUs, the glasslites may be compressed against the spacer. In some configurations,there are problematic issues created by compressing a metallic,conductive spacer against a conductor (i.e., the conductive wires, busbars, or other connections) of the electrochromic device. Someconventional sealants may not suffice as insulators in such conditions.

In order to orient the reader to the embodiments of IGUs disclosedherein, a brief discussion of electrochromic devices, edge deletion, andIGUs is provided. This initial discussion of electrochromic devices,edge deletion, and IGUs is provided for context only, and thesubsequently described embodiments of spacers are not limited to thespecific features and fabrication processes of this initial discussion.

Particular examples of electrochromic devices formed on substrates aredescribed with reference to FIGS. 1A-1C. FIG. 1A is a cross-sectionalrepresentation (along cut X-X as depicted in FIG. 1C) of anelectrochromic lite, 100, which is fabricated starting with a glasssheet, 105. FIG. 1B shows a different view from Y-Y as depicted in FIG.1C; i.e., FIG. 1B shows a view of electrochromic lite 100 from thebottom edge and in the plane of the paper (e.g., 90 degrees from thecross-sectional view shown in FIG. 1A). FIG. 1C shows a top-down view ofelectrochromic lite 100.

FIG. 1A shows an electrochromic lite after edge deletion (describedbelow), laser scribing, and bus bar attachment. Glass sheet 105 has adiffusion barrier, 110, and a first transparent conducting oxide (TCO)layer, 115, on the diffusion barrier. First TCO layer 115 is the firstof two conductive layers that form the electrodes of the electrochromicdevice fabricated on the glass sheet.

In some embodiments, the glass sheet as supplied may include thediffusion barrier layer as well as the first TCO layer. Thus, in someembodiments, an electrochromic stack, 120, and then a second TCO layer,125, may be formed in the fabrication of electrochromic lite 100. Theelectrochromic stack is typically a series of layers, e.g., anelectrochromic layer, an electrolyte layer, and an ion storage layer;however, in some embodiments electrochromic stack 120 is anelectrochromic layer and an ion storage layer with an interfacial regionthat acts as an electrolyte layer. Examples of electrochromic devicesincluding such stacks are described in U.S. patent application Ser. No.12/772,055, filed Apr. 30, 2010, titled “Electrochromic Devices,” andnaming Wang et. al as inventors; the application is incorporated byreference in its entirety herein. In some embodiments, electrochromicstack 120 and second TCO layer 125 are fabricated in an integrateddeposition system where glass sheet 105 does not leave the integrateddeposition system at any time during fabrication of the stack. In someembodiments, first TCO layer 115 is also formed using the integrateddeposition system where glass sheet 105 does not leave the integrateddeposition system during deposition of the stack/layers. In someembodiments, all of the layers (diffusion barrier 110, first TCO layer115, electrochromic stack 120, and the second TCO layer 125) aredeposited in the integrated deposition system where glass sheet 105 doesnot leave the integrated deposition system during deposition of thestack/layers.

After formation of the electrochromic device, edge deletion and laserscribing are performed. FIG. 1A depicts areas, 140, where portions ofthe electrochromic device have been removed from a perimeter regionsurrounding the laser scribe trenches, 130, 131, 132, and 133 (see alsoFIGS. 1B and 1C). The laser scribe trenches pass through the second TCOlayer and the electrochromic stack, but not through the first TCO. Thelaser scribe trenches are made to isolate portions of the electrochromicdevice, 135, 136, 137, and 138, from the operable electrochromic device.The isolated portions of the electrochromic device are portions thatwere potentially damaged during edge deletion and/or fabrication. If theedge deletion produces a clean cut edge to the device stack, e.g., usinglasers for the removal of material in the edge deletion, then theseisolation trenches may not be needed.

In some embodiments, laser scribe trenches 130, 132, and 133 passthrough the first TCO layer to aide in isolation of the device. Notethat laser scribe trench 131 does not pass through the first TCO layer;otherwise, it would cut off bus bar 2's electrical communication withthe first TCO layer and thus the electrochromic stack.

The laser or lasers used for the laser scribing are typically, but notnecessarily, pulse-type lasers, for example, including diode-pumpedsolid state lasers. For example, the laser scribing can be performedusing a suitable laser from IPG Photonics (Oxford, Mass.), or fromEkspla (Vilnius, Lithuania). Scribing can also be performedmechanically, for example, with a diamond tipped scribe. One of ordinaryskill in the art would appreciate that the laser scribing can beperformed at different depths and/or performed in a single processwhereby the laser cutting depth is varied, or not, during a continuous(or not) path around the perimeter of the electrochromic device. In someembodiments, the edge deletion is performed to the depth below the firstTCO layer. In some embodiments, a second laser scribe is performed toisolate a portion of the first TCO layer near the edge of the glasssheet from that toward the interior, as depicted in FIGS. 1A-C, forexample. In some embodiments, this scribe is at least along the edge ofelectrochromic lite 100 where bus bar 2 is applied to the first TCOlayer and is between bus bar 2 and the edge of electrochromic lite 100.

After laser scribing is complete, bus bars are attached. In FIGS. 1A-C,a non-penetrating bus bar 1 is applied to second TCO layer 125.Non-penetrating bus bar 2 is applied to an area where the device was notdeposited (for example, from a mask protecting first TCO layer 115 fromdevice deposition), in contact with first TCO layer 115 or, as depictedin FIG. 1A, where edge deletion was used to remove material down tofirst TCO layer 115. In this example, both bus bar 1 and bus bar 2 arenon-penetrating bus bars. A penetrating bus bar is one that is typicallypressed into and through the electrochromic stack to make contact withthe TCO layer at the bottom of the stack. In some embodiments, asoldering step, where a contact is soldered to a bus bar, may serve topenetrate the electrochromic stack and establish electrical contact to alower conducting layer. A non-penetrating bus bar is one that does notpenetrate into the electrochromic stack layers, but rather makeselectrical and physical contact on the surface of a conductive layer,for example, a TCO layer. Both types are suitable for use with theembodiments disclosed herein.

Edge deletion may be performed on a window where edge portions of anelectrochromic device are removed prior to integration of the windowinto the IGU. The edge portions may include, for example, regions of“roll off” where layers of an electrochromic stack that are normallyseparated contact one another due to non-uniformity in the layers nearthe edge of the electrochromic device.

Further, edge deletion may be employed for removal of one or moreelectrochromic device layers that would otherwise extend to underneaththe IGU. In some embodiments, isolation trenches are cut and theisolated portions of the electrochromic device on the perimeter of theelectrochromic lites are removed by edge deletion. The process ofperforming edge deletion is, in some embodiments, a mechanical processsuch as a grinding or sandblasting process. An abrasive wheel may beemployed for grinding. In some embodiments, edge deletion is done bylaser, where a laser is used to ablate electrochromic material from theperimeter of the electrochromic lite. The process may remove allelectrochromic device layers, including the underlying TCO layer, or itmay remove all electrochromic device layers except the bottom TCO layer.The latter case is appropriate when the edge deletion is used to providean exposed contact for a bus bar, which may be connected to the bottomTCO layer. In some embodiments, a laser scribe is used to isolate thatportion of the bottom TCO layer that extends to the edge of the glasssheet from that which is connected to the bus bar (sometimes referred toas a bus bar pad or contact pad) in order to avoid having a conductivepath to the electrochromic device from the edge of the glass sheet.

When edge deletion is employed, it can be performed before or after theelectrochromic lites are cut from the glass sheet (assuming that litesare cut from a larger glass sheet as part of the fabrication process).In some embodiments, edge deletion is performed in some edge areas priorto cutting the electrochromic lites and again after they are cut. Insome embodiments, all edge deletion is performed prior to cutting theelectrochromic lites. In embodiments employing edge deletion prior tocutting the electrochromic lites, portions of the electrochromic deviceon the glass sheet can be removed in anticipation of where the cuts (andthus edges) of the newly formed electrochromic lites will be. In mostfabrication processes, after edge deletion, bus bars are applied to theone or more electrochromic lites.

After the electrochromic devices with bus bars are fully assembled onthe glass sheets, IGUs are manufactured using the one or moreelectrochromic lites (e.g., refer to FIG. 3A and the associateddescription). Typically, an IGU is formed by placing a primary sealingspacer, which may include a gasket or sealing material (e.g., PVB(polyvinyl butyral), PIB (polyisobutylene), or other suitable elastomer)and a rigid spacer around the perimeter of the glass sheet. The primarysealing spacer may also be referred to as a primary sealant. In thedisclosed embodiments, the primary sealing spacer includes a metalspacer, or other rigid material spacer, and sealing material between themetal spacer and each glass lite. After the lites are joined to theprimary sealing spacer, a secondary seal may be formed around the outerperimeter of the primary sealing spacer. The secondary seal may be, forexample, a polymeric material that resists water and that addsstructural support to the IGU. Typically, but not necessarily, adesiccant is included in the IGU frame or spacer during assembly toabsorb any moisture and/or organic volatiles that may diffuse from thesealant materials. In some embodiments, the primary sealing spacersurrounds the bus bars and electrical leads to the bus bars extendthrough the seal. Typically, but not necessarily, the IGU is filled withinert gas such as argon. The completed IGU can be installed in, forexample, a frame or curtain wall and connected to a source ofelectricity and a controller to operate the electrochromic window.

As described above, after the bus bars are connected, the electrochromiclite is integrated into an IGU, which includes, for example, wiring forthe bus bars and the like. In the embodiments described herein, both ofthe bus bars are inside the primary seal of the finished IGU. FIG. 2Ashows a cross-sectional schematic diagram of the electrochromic windowas described in relation to FIGS. 1A-C integrated into an IGU, 200. Aspacer, 205, is used to separate electrochromic lite 201 from a secondlite, 210. Second lite 210 in IGU 200 is a non-electrochromic lite,however, the embodiments disclosed herein are not so limited. Forexample, lite 210 can have an electrochromic device thereon and/or oneor more coatings such as low-E coatings and the like. Lite 201 can alsobe laminated glass, such as depicted in FIG. 2B (lite 201 is laminatedto reinforcing pane, 230, via resin, 235). Between spacer 205 and thefirst TCO layer of the electrochromic lite is a primary seal material,215. This primary seal material is also between spacer 205 and secondglass lite 210. Around the perimeter of spacer 205 is a secondary seal,220. Bus bar wiring/leads traverse the seals for connection tocontroller. Secondary seal 220 may be much thicker that depicted. Theseseals aid in keeping moisture out of an interior space, 202, of the IGU.They also serve to prevent argon or other gas in the interior of the IGUfrom escaping.

For further context, FIG. 3A depicts an example of an electrochromicwindow fabrication process, 300. In electrochromic window fabricationprocess 300 an electrochromic lite, 305, having an electrochromic device(not shown, but for example on surface W) and bus bars, 310, whichdeliver power to the electrochromic device, is matched with anotherglass lite, 315. During fabrication of an IGU, 325, a spacer, 320, issandwiched in between and registered with substrates/lites 305 and 315.IGU 325 has an associated interior space defined by the faces of thewindows/lites in contact with spacer 320 and the interior surfaces ofthe spacer. Spacer 320 is typically a sealing spacer, that is, itincludes a spacer and sealing material between the spacer and eachsubstrate where they adjoin in order to hermetically seal the interiorregion and thus protect the interior region from moisture and the like.Once the glass lites are sealed to the spacer, secondary sealingmaterial may be applied around the perimeter edges of the IGU in orderto impart not only further sealing from the ambient, but also furtherstructural rigidity to the IGU. IGU 325 may be wired to a power supplyand/or controller via wires, such as wires, 330. The IGU is supported bya frame, 340, to create a window assembly, 335. Window assembly 335 maybe separately connected to a controller (not shown). The controller mayalso be connected to one or more sensors in the window or frame.

FIG. 3B depicts an example of a window assembly, 335, including frame340. The viewable area of the window assembly is indicated on thefigure, inside the perimeter of frame 340 (using a heavy black line). Asindicated by dotted lines, inside frame 340 is IGU 325 which includestwo glass lites separated by sealing spacer 320, shaded in gray.

In some embodiments, an edge bumper is employed to protect the edges ofthe glass after incorporation in the IGU. This protection allows the IGUto be safely transported from manufacturer to installation, for example.In some embodiments, the protective bumper is a U-channel cap which fitsover the glass edges around the perimeter of the IGU. It may be madefrom an elastomeric or plastic material. In some embodiments, the edgebumper is a vinyl cap.

FIG. 4 is a facing or front view of an IGU, 400, which includeselectrochromic lite 305 as depicted in FIG. 3A. Electrochromic lite 305has bus bars 310 fabricated on an electrochromic device (not depicted).FIG. 4 shows the relative configurations of the spacer, theelectrochromic lite, the wiring, and so forth. Spacer 320 surrounds busbars 310 and overlays leads to the bus bars. In some embodiments, thebus bar leads may be a conductive ink. Wiring, 405, connects to bus bars310 via the bus bar leads. Wiring 405 further occupies at least aportion of the secondary seal area and then passes out of IGU 400. Insome embodiments, wiring 405 may be insulated (i.e., the wiring may havea conductive metal core covered with an insulating material, forexample).

Because the spacer in a conventional IGU is made from a metal, such as asteel hollow bar or a stainless steel hollow bar, for example, it canpossibly short out one or more features contained in an electrochromicdevice employed in an electrochromic window. Using IGU 325 (see FIG. 3A)as an example, lite 315 is pressed together with electrochromic lite 305with spacer 320 and a primary sealant material there between. With thebus bar leads extending under spacer 320, there is a chance of shortingbetween the bus bar leads and the spacer.

In some embodiments, rather than bus bar leads traversing the area wherethe spacer presses against the primary sealant material, wires 405 maytraverse the area. However, the compression used to assemble an IGU maycompromise the integrity of insulation on wires 405. In someembodiments, wires 405 may be thin, flat wires (e.g., braided wirecabling) with insulation over the wires. In some embodiments, the wiresrun between the spacer and the lite, rather than leads as depicted inFIG. 4. Even if thin, flat wires are used, there still may be issueswith shorting.

FIG. 4 further shows examples of three modes of potential shorting ofthe electrochromic device to the spacer and consequent failure of theelectrochromic device. Reference X illustrates a potential short betweenthe bus bar and the spacer at a “crossover point,” e.g., the bus barlead. The crossover point can be understood as the electrical connectionbetween the bus bar of the electrochromic device and an externalconnection to the bus bar from outside the interior space of the IGU.Typically, the external connection provides power from a voltage orother power source to the bus bar. The bus bar provides power to one ofthe two sheet electrodes of the electrochromic device. In the aboveembodiments, the sheet electrodes are typically transparent conductiveoxides (TCOs), such as indium tin oxide (ITO) or TEC (a fluorinated tinoxide conductive layer provided on glass lites marketed under thetrademark TEC Glass™ by Pilkington). The contact between the bus barlead and the spacer shown as reference X is a region where the bus barlead (or a wire) extends across the spacer from the interior space ofthe IGU to the secondary seal area. The bus bar lead, which is anextension of the bus bar, is sometimes referred to as a “bus bar exit.”Whichever wiring configuration is used, there is a potential forshorting with a conductive spacer. As will be described in more detailbelow, one mode of addressing this potential problem of an electricalshort between the spacer and the bus bar lead is by creating a smallnotch or “mouse hole” in the underside side of the spacer that contactsthe lite in order to allow room for the bus bar lead (or wire) to passbetween the lite and the spacer without contacting the spacer.

A second potential short or failure area depicted in FIG. 4 isillustrated by reference Y. In area Y, between the bus bar and thespacer, it is possible that the bus bar itself may contact theconductive spacer. Because the bus bar is a relatively long structure,oriented along one edge of the window, the bus bar could contact acorresponding point on the metal spacer anywhere along the length of thebus bar. Typically the bus bar is situated as close as possible to thespacer without touching it, in order to maximize viewable area of thewindow. Because of the tight tolerances employed in manufacturing anelectrochromic device, it is possible that there will be some minormisalignment of the bus bar and/or the spacer resulting in contact inthe area indicated by Y. The bus bar itself typically resides on aninactive area of the electrochromic device, for example, behind a laserscribe line, and the bus bar material used is often light in color. Withthis also in mind, the bus bar is typically placed very close to theedge of the window at the edge of the electrochromic device. As aconsequence, it is typically placed very close to the spacer.

The third mode of potential shorting and failure is illustrated byreference Z. As shown, a contact can occur between the spacer and someamount of the transparent conductive electrode employed in theelectrochromic device. While it is typical to remove some or all of theelectrochromic device stack, for example, in an edge delete process, itis not uncommon to have some small amount of an underlying conductivefilm such as ITO or TEC remain near the edge of the device on thewindow. As described above, the primary sealant, such as PIB or PVB,typically separates the metal spacer bar from the glass lite with thetransparent conductive electrode. However, the primary sealant candeform under pressure and it is not uncommon for the sealant to besqueezed out of the seal area over time. As a consequence, there is asignificant risk that the spacer will electrically contact some of thetransparent conductive electrode and cause a short.

It should be understood that the design placement of the bus bar, theconnectors/leads, the location of the conductive electrode layers, etc.,are specified with very tight tolerances, e.g., on the order of about afew millimeters or less. It has been found in practice that thespecification may not be met. Therefore, each of the three depictedmodes of shorting failure represents a significant design challenge. Thefollowing discussion of FIGS. 5-11B illustrate certain embodiments thataddress one or more of these potential modes of failure. One of ordinaryskill in the art would appreciate that, where useful, combinations ofthese embodiments are contemplated as individual embodiments herein.Certain embodiments are described in terms of an IGU; however, oneembodiment is a spacer as described herein, or a sub-assembly of an IGUdescribed herein.

FIG. 5A shows an example of a cross section, 500, of an edge region ofan IGU where the spacer of the IGU and the bus bar reside. Asillustrated, a spacer, 510, is sandwiched between two sheets of glassnear the edge of the IGU. In a typical design, the glass interfacesdirectly with a primary seal material, 515, (e.g., a thin elastomericlayer, such as PIB or PVB), which is in direct contact with spacer 510.In some embodiments, spacer 510 may be metal spacer, such as a steelspacer or a stainless steel spacer, for example. This three-partinterface (i.e., glass/primary seal material/spacer) exists on both atop piece of glass and a bottom piece of glass. Spacer 510 may have ahollow structure, as depicted in FIG. 5A. In some embodiments, thespacer may have a substantially rectangular cross section. At a minimum,spacers described herein have at least two surfaces, each substantiallyparallel to the lites of the IGU in which they are to be incorporated.The remaining cross section, e.g., surfaces of the spacer that face theinterior space of the IGU and the exterior, secondary seal area, spacemay have any number of contours, i.e., they need not be flat, but maybe. In the example depicted in FIG. 4, spacer 510 has two surfaces, oneach face that forms the primary seal that are substantially parallel tothe glass lites of the IGU. In some embodiments, the top and bottomouter corners of the spacer are beveled and/or rounded to produce ashallower angle in these areas. Rounding, beveling, or smoothing may beincluded to ensure there are no sharp edges that might enhanceelectrical shorting. An electrochromic device stack, 505, is fabricatedon the lower glass lite, as depicted. A bus bar, 520, is located onelectrochromic device stack 505 in order to make electrical contact withone of the electrodes of the device. In this example, bus bar 520 isbetween spacer 510 and the lower glass lite. This is accomplished byconfiguring one of the aforementioned surfaces below (see top surface ofspacer 510) or above (see bottom surface of spacer 510) the othersurface on the face of the spacer that forms the primary seal with theglass surface. This configuration of surfaces forms “notch” 501; seefurther description below. Primary seal material 515 serves as aninsulating layer between bus bar 520 and spacer 510.

There are two primary distinctions between a normal spacer design andspacer 510 shown in FIG. 5A. First, spacer 510 is relatively thicker(wider) in the direction parallel to the glass sheet (i.e., a largerfootprint as would be typical from the view depicted in FIG. 3B, forexample). A conventional metal spacer is approximately 6 millimeters inwidth. Spacer 510 is about two times to about two and one half times(about 2× to about 2.5×) that width. For example, spacer 510 may beabout 10 millimeters to about 15 millimeters wide, about 13 millimetersto about 17 millimeters wide, or about 11 millimeters wide. Thisadditional width may provide a greater margin of error in a sealingoperation compared to a conventional spacer.

The second significant distinction of spacer 510 from a conventionalspacer is in the use of recesses or notches 501 on the upper and lowerinner corners of spacer 510. In some embodiments, a spacer may includetwo notches, and in some embodiments, the spacer may include one notch.Two notches, e.g., as depicted in FIG. 5A, may be used for an IGUcontaining two electrochromic lites, or may be useful in fabricatingIGUs with only one electrochromic light. When using a spacer with twonotches in an IGU containing one electrochromic lite, there is no needfor special placement of a single notch toward the electrochromic lite.In some embodiments, a recess or notch may extend from a corner of oneside of the rectangular cross section of the spacer to a point along theone side of the rectangular cross section of the spacer. At least onenotch provides an area for covering the bus bar formed on the glasssurface and/or covering the bus bar formed on electrochromic devicestack 505 formed on the glass surface. In some embodiments, the bus baris about 2 millimeters to about 3 millimeters in width and about 0.01millimeters to about 0.1 millimeter in height (thickness). The bus barlength depends on the window size. In some embodiments, a bus bar mayhave a length about the length of the electrochromic device. The addedwidth, along with the “notched” profile of spacer 510 that accommodatesthe bus bar, creates a region of “encapsulation” whereby the bus bar isunlikely to contact the spacer at any point along the length of the busbar, but is encapsulated in the primary sealant.

In some embodiments, the portion of the spacer's face that does notinclude the notch (i.e., the outer portion of the spacer) isapproximately the same width as a normal spacer employed innon-electrochromic IGU applications. As depicted in FIG. 5A, bus bar 520is entirely covered by the spacer 510. As a consequence, the bus bar isnot visible to a user of the window.

In FIG. 5A, electrochromic device stack 505 extends underneath bus bar520 and partially into the region formed by notch 501 in spacer 510. Asnoted above, an electrochromic device stack typically includes aconductive electrode layer such as ITO or TEC. Electrochromic devicestack 505 may be entirely removed from the edge of the glass surface byan edge deletion process, described above. However, the removal by edgedeletion may not extend entirely up to the edge of the bus bar, as thiswould be unacceptable given normal process tolerances. Therefore,electrochromic device stack 505 may extend just slightly beyond bus bar520, e.g., while still residing in notch 501.

FIG. 5B shows examples of different implementations of bus bars. Bus bar520 may be a non-penetrating bus bar that resides on the ITO ofelectrochromic device stack 505 (see 525), a penetrating bus bar thatmakes electrical contact with the TEC of electrochromic device stack 505(where a scribe electrically isolates the bus bar from shorting to theITO, see 530), or a non-penetrating bus bar that resides on the TEC(lower electrode), where the layers of electrochromic device stack 505were removed so that the bus bar could be fabricated directly on theTEC, rather than having to penetrate the stack (see 535).

Spacer 510, which is wider than conventional spacers, as well as notches501 in spacer 510, provide additional space for primary seal material515 (e.g., PIB). This feature, along with the notch or notches on thetop and/or bottom inside edges of the spacer, give spacer 510 variousadvantages that are particular to electrochromic devices incorporated inIGUs. For example, a wider primary seal area provides better containmentof argon or other gas within the IGU interior as well as protection ofthe IGU from moisture and other gasses in the ambient environment. Thesealing of the IGU secondary seal also may be improved and may providebetter structural integrity than a conventional IGU design.Additionally, the IGU may color all the way to the edge defined by theinterior perimeter of the spacer. With the bus bars hidden underneaththe notch in the spacer, there will be no bright sight lines createdeither by the inactive area where the bus bar is placed or by therelatively lightly colored material used to fabricate the bus bar.

Still further, the disclosed embodiment will satisfy industryexpectations for an IGU that contains a primary seal having aglass/primary seal material (e.g., PIB)/metal spacer construction.Additionally, because the electrochromic device may employ an edgedeletion down to the level of the glass (or the diffusion barrier) andfrom the glass edge to an area where a notch of the bus bar will form aportion of the primary seal and thus provide more space between the busbar and spacer, the likelihood of shorting between the electrochromicdevice electrode and the spacer is greatly reduced. FIG. 5C showscross-sections of other spacers, 540-575, in accord with embodimentsdescribed herein, each spacer having at least one notch 501.

As noted, embodiments described herein, including notched embodiments,may employ a channel or “mouse hole” under an edge of the spacer where alead or a connector to the bus bar may run to allow connection to anoutside power source (described further herein). One embodiment is thespacer as described in relation to FIGS. 5A-C including a channel on oneor both faces of the spacer that form the primary seal with the lite orlites. As also noted, the bus bar lead is typically orientedsubstantially perpendicular to the line of the bus bar itself. It istypically made from the same material as the bus bar (e.g., silver,conductive ink, or other highly conductive material). The channel ormouse hole may be formed in a metal spacer, e.g., stainless steel, or bepart of a connector key that joins two ends of a slotted, open, spacer.This is described in more detail below.

FIG. 6 shows two embodiments of connector keys. A connector key istypically used to join two ends of a spacer. As noted above, a spacermay be made from hollow metal rectangular pieces. One or more of thesepieces are bent into an overall rectangular-shaped piece that forms thespacer. This rectangular-shaped spacer is sized and shaped to mate withthe perimeter of the glass used to form an IGU. Two ends of the one ormore pieces of tubular spacer material are joined by a connector key.For example, an end of the tubular spacer material may slide over aportion of a connector key, and the other end of the tubular spacermaterial may slide over another portion of the connector key.Alternatively, as depicted in FIG. 6, the ends of the metal spacer slideinto the connector key.

Each of the connector keys in FIG. 6 has been modified to accommodate abus bar lead. In some embodiments, a metal spacer and a primary sealmaterial form a barrier between an interior region of the windowassembly and an exterior region of the window assembly. A lead or a wirepasses from an electrode of an optically switchable device on theinterior region of the window assembly, under a connector key, and tothe exterior region of the window assembly. The connector key is not inelectrical communication with the lead or the wire.

In embodiment 600, a connector key, 605, joins two ends, 620, of thespacer. In some embodiments, the spacer may be a metal spacer, such as asteel spacer or a stainless steel spacer, for example. In someembodiments, the spacer may have a substantially rectangular crosssection. In some embodiments, the spacer may be hollow. The two ends ofthe spacer, 607, slide into the respective ends of connector key 605.The connector key and spacer are configured so that when joined, thesurfaces that are to come into contact with the glass are substantiallyco-planar. Connector key 605 has a middle section that is made from ametal, particularly a crimpable metal, such as steel or stainless steel,for example. The bottom portion of the middle region of connector key605 is made from this crimpable metal and is in fact crimped to producethe channel 609 or mouse hole under which the bus bar lead passes. Ofcourse, connector key 605 could be cast or machined to achieve the sameresult, but stamped or crimped metal is more economical.

In some embodiments, instead of a bus bar lead passing under channel609, wiring for an electrode may pass under channel 609. For example, insome embodiments, the wire may be thinner than the thickness (i.e.,height) of the channel. In some embodiments, when a thin wire is used,the thickness (i.e., height) of the channel may be reduced.

In embodiment 610, a connector key, 615, joins two ends, 620, of thespacer. The two ends of the spacer, 617, slide into the ends ofconnector key 615. Connector key 615 is an electrically non-conductiveor insulating material (e.g., a plastic). Connector key 615 may or maynot have a channel or mouse hole cut into it. Typically, such a channelwill be unnecessary because connector key 615 is a non-conductive orinsulating material, thereby eliminating the possibility of a shortbetween the connector key and the bus bar lead. Thus, the connector keyand the lead will not be in electrical communication.

It should be noted that the connector key normally sits at a randomlocation in the spacer. This is because the tubular metal pieces used tomake the spacer typically come in standard or fixed lengths. Theselengths may be used to construct a rectangular spacer of effectivelyarbitrary size, as dictated by the size of the window and the associatedIGU. In accordance with the embodiments shown FIG. 6, the spacer may beconstructed in a manner in which the connector key lines up with atleast one of the bus bar leads. In some embodiments, the spacer isdesigned so that two separate connector keys are specifically aligned tocoincide with the position of the two bus bar leads at opposite sides ofthe electrochromic device. In some embodiments, one of the connectorkeys is forced into alignment on the spacer with the bus bar lead. Insuch embodiments, the opposite bus bar lead may pass through a channelcreated in the body of the tubular metal used to make the spacer. Such achannel may be created by, e.g., forming a dent or a crimp in thetubular metal piece at a location coinciding with the bus bar lead.

In some other embodiments, the spacer is constructed using conventionalconnector keys. The spacer may then be dented or crimped at thelocations where the bus bar lead passes.

FIG. 7 shows an example of a detailed cross-sectional view of a crimpedconnector key aligned on a glass sheet with an electrochromic devicefabricated thereon. Particularly, the detailed view, 700, shows achannel (mouse hole), 705, in the middle portion of a connector key,710, where a bus bar lead, 715, on a glass lite, 720, passes through thechannel. Various sample dimensions are provided in FIG. 7. It should beunderstood that these are only examples and that many other dimensionsmay be appropriate. In some embodiments, bus bar lead 715 may have aheight, 725, of about 0.05 millimeters to about 0.1 millimeters. In someembodiments, channel 705 may have a height, 730, of about 0.1millimeters to about 1 millimeter. In some embodiments, channel 705 mayhave a width in connector key 710 of about 4.5 millimeters to about 10millimeters. In some embodiments, a clearance, 735, that may be desiredon either side of bus bar 715 may be about 1.5 and about 2.5millimeters.

A crimping process that may be used to form a crimped metal connectorkey may have tolerances associated with the process. Therefore, thechannel formed in a connector key may be specified to be somewhat largerthan what is desired to account for the tolerances in the process.

FIG. 8 shows an example of a cross-sectional illustration of a spacerwhich has a notch on the bottom to accommodate the full length of thebus bar. As shown in FIG. 8, a spacer, 805, is between two glass lites,810 and 815. In some embodiments, spacer 805 may be a metal spacer, suchas a steel spacer or a stainless steel spacer, for example. In someembodiments, spacer 805 may have a substantially rectangular crosssection. In some embodiments, spacer 805 may be hollow. Spacer 805includes a notch or recess, 820, to accommodate a bus bar, 825. Notch orrecess 820 may form a channel that accommodates the length of bus bar825. Notch 820 should be distinguished from a channel or a “mouse hole”in the spacer which may accommodate a bus bar lead. An electrochromicdevice stack, 802, is fabricated on glass lite 815. Bus bar 825 locatedon electrochromic device stack 802 makes electrical contact with one ofthe electrodes of electrochromic device stack 802.

Notch 820 in spacer 805 resides in the middle of the underside of spacer805. The dimensions of notch 820 are suitable to accommodate bus bar825, factoring in tolerances of the process used to form the notch, asdiscussed above. In some embodiments, the notch width is about 2millimeters to about 5 millimeters, and the notch height is about 0.1millimeters to 1 millimeter. In some embodiments, the notch width isabout 3 millimeters to 4 millimeters, and the notch height is about 0.1millimeter to about 0.5 millimeters.

Comparing notch 820 shown in FIG. 8 to notch 501 shown in FIG. 5A, notch820 is in the middle of the underside of the spacer and notch 501 is atthe interior edge of the underside of the spacer. In other regards,however, the embodiment shown in FIG. 8 may be similar to the embodimentshown in FIG. 5A. For example, many of the dimensions and other designfeatures described with respect to FIG. 5A may apply equally to FIG. 8.Spacer 805 may be relatively thicker (wider) in the direction parallelto the glass sheet compared to conventional metal spacers. Aconventional metal spacer is approximately 6 millimeters in width.Spacer 805 is about two times to about two and one half times (about 2×to about 2.5×) that width. For example, spacer 805 may be about 10millimeters to about 15 millimeters, about 13 millimeters to about 17millimeters, or about 11 millimeters wide. This additional width mayprovide a greater margin of error in a sealing operation compared to aconventional spacer. In some embodiments, the bus bar is about 2millimeters to about 3 millimeters in width and about 0.01 millimetersto about 0.1 millimeter in height (thickness). The bus bar lengthdepends on the window size. In some embodiments, a bus bar may have alength about the length of the electrochromic device. The basic IGUprimary seal is comprised of interfaces between glass lites 810 and 815and primary seal material (e.g., PIB), 830, and between primary sealmaterial 830 and spacer 805.

In some embodiments, the channel for the bus bar lead is located as inthe embodiment described with respect to FIGS. 6 and 7, but need onlypenetrate part way under the spacer because the bus bar resides midwayunderneath the spacer. In some embodiments, the bus bar lead channelresides on an outside edge of the spacer or on an outside edge of acorner of the spacer.

In some embodiments, the electrochromic device stack 802 when in acolored state may color all the way under the spacer such thatelectrochromic device stack 802 is substantially uniformly colored.Further, the bus bar may not be visible.

FIG. 9 shows an example of a cross-sectional illustration of a spacer inwhich the primary seal material (e.g., PIB) is modified to resistcompression. With the primary seal material modified to resistcompression, there may be reduced chances of the spacer contacting thebus bar and creating a short. As shown in FIG. 9, a spacer, 905, isbetween two glass lites, 910 and 915. In some embodiments, spacer 905may be a metal spacer, such as a steel spacer or a stainless steelspacer, for example. In some embodiments, spacer 905 may have asubstantially rectangular cross section. In some embodiments, spacer 905may be hollow. An electrochromic device stack, 920, is fabricated onglass lite 915. A bus bar, 925, located on electrochromic device stack,920, makes electrical contact with one of the electrodes of the device.In some embodiments, a bus bar may have a length about the length of theelectrochromic device stack. A primary seal material (e.g., PIB), 930,joins glass lite 910 to spacer 905. A primary seal material (e.g., PIB),935, joins glass lite 915 to spacer 905. Primary seal material 935 isimpregnated with mechanical supports 940 or other support material thatmay prevent spacer 905 from being forced into a position where itapproaches the glass lite 915 surface and possibly into contact with busbar 925. Mechanical supports 940 may include electrically non-conductiveor insulating particles, such as glass particles, plastic particles,polycarbonate particles, or ceramic particles, for example. In someembodiments, the non-conductive or insulating particles may be spheresor may be substantially spherical. Such particles may impact orotherwise be compressed into a bus bar or bus bar lead, but since theyare non-conductive and spaced apart within the sealant matrix, there isno chance of shorting as the particles physically prevent contactbetween the spacer and the conductive components of the electrochromicdevice. The particles should be of sufficient size to prevent thisphysical contact, while generally having an average diameter that issmaller than the width of the spacer so as to avoid traversing the widthof the spacer and compromising the primary seal integrity. In oneembodiment, the particles are spheres having an average diameter ofabout 0.5 millimeters to about 3 millimeters, in another embodimentabout 0.5 millimeters to about 1.5 millimeters, and in yet anotherembodiment about 0.5 millimeters to about 1 millimeter.

In some other embodiments, instead of impregnating the primary sealmaterial with mechanical supports, the primary seal material is mademore viscous or mechanically resistant to compression. This may beaccomplished by, for example, increasing the cross-linking in theprimary seal material when the primary seal material is a polymericmaterial.

Of course, as with the other designs, some provision may be made forpassing the bus bar lead underneath the spacer. This can be accomplishedwith a modified connector key or a channel/tunnel under a portion of thespacer, as described above.

FIG. 10 shows an example of a cross-sectional illustration of a spacerin which the spacer itself is modified so that one of its four walls ismade of, or coated with, an electrically non-conductive or insulatingmaterial. The non-conductive or insulating material may be, for example,a polymeric material or a plastic. As shown in FIG. 10, a spacer, 1005,is between two glass lites, 1010 and 1015. In some embodiments, spacer1005 may have a substantially rectangular cross section. Anelectrochromic device stack, 1020, is fabricated on glass lite 1015. Abus bar, 1025, located on electrochromic device stack 1020 makeselectrical contact with one of the electrodes of the device. In someembodiments, a bus bar may have a length about the length of theelectrochromic device stack. A primary seal material (e.g., PIB), 1030,joins glass lites 1010 and 1015 to spacer 1005.

Spacer 1005 is a hollow spacer with three sides of the spacer made froma metal (e.g., steel or stainless steel) and one side, 1035, is made outof an electrically non-conductive material. The electricallynon-conductive or insulating material may be a polymeric material or aplastic, for example. Side 1035 is a c-shaped piece which mates with themetal portion (e.g., much like the U-channel described above with regardto protecting the IGU, but smaller so as to fit within the IGU, as partof the spacer). Together, the metal and plastic portions form a tubularstructure as with a conventional all-metal spacer. Spacers of the typedepicted in FIG. 10 are available from Technoform (of Twinsburg, Ohio).

Side 1035 of spacer 1005 faces towards the inside of the IGU, and istherefore the portion of spacer 1005 that comes into closest proximitywith bus bar 1025. In accordance with this embodiment, if spacer 1005 ismoved into a position where it effectively touches glass lite 1015 andpossibly bus bar 1025, side 1035, which is insulating, will contact busbar 1025. With side 1035 contacting bus bar 1025, shorting between themetal portions of spacer 1005 and bus bar 1025 is avoided.

Of course, as with the other designs, some provision may be made forpassing the bus bar lead underneath the spacer. This can be accomplishedwith a modified connector key or a channel/tunnel under a portion of thespacer, as described above.

FIGS. 11A-11C show examples of diagrams of an IGU with a two-partspacer. The IGU, 1100, shown in FIG. 11A includes electrochromic lite,305, as depicted in FIG. 3A. Electrochromic lite 305 has bus bars, 310,fabricated on an electrochromic device (not depicted). In someembodiments, a bus bar may have a length about the length of theelectrochromic device. IGU 1100 includes a two-part spacer, including aninterior electrically non-conductive or insulating portion or spacer,1105, and an exterior metal portion or spacer, 1110. In someembodiments, non-conductive or insulating spacer 1105 and metal spacer1110 may have substantially rectangular cross sections. Non-conductiveor insulating spacer 1105 may be made from a polymeric material, aplastic material, or a foam material, for example. In some embodiments,the non-conductive or insulating spacer 1105 is a Triseal spaceravailable from Edgetech USA (of Cambridge, Ohio). Metal spacer 1110 maybe made from steel or stainless steel, for example. Metal spacer 1110may be a conventional spacer. Cross section J-J′ includes a channel inboth non-conductive or insulating spacer 1105 and metal spacer 1110 forthe bus bar leads. Cross section K-K′ does not include a channel.

As shown in cross section K-K′, non-conductive or insulating spacer 1105includes a notch or recess, 1115, to accommodate bus bar 310. The notchmay form a channel in a side of the non-conductive or insulating spacer.An electrochromic device stack (not shown) is fabricated on glass lite1130. Bus bar 310 located on the electrochromic device stack makeselectrical contact with one of the electrodes of the device. Withnon-conductive or insulating spacer 1105 situated on top of bus bar 310,the risk of a short between bus bar 310 and metal spacer 1110 isreduced. An edge delete operation may still be performed on glass lite1130 down to the glass so that metal spacer 1110 does not contact theconductive electrodes of the electrochromic device stack. The IGUprimary seal is comprised of interfaces between glass lites 1130 and1135 and primary seal material (e.g., PIB), 1140, and between primaryseal material 1140 and non-conductive or insulating spacer 1105 andmetal spacer 1110.

In some embodiments, metal spacer 1110 may have about the same width asa conventional spacer; i.e., about 6 millimeters wide. In someembodiments, metal spacer 1110 may have a smaller width than aconventional spacer. For example, metal spacer 1110 may be about 4millimeters wide. Regardless of whether metal spacer 1110 has the samewidth or has a smaller width than a conventional spacer, the overalldesign of metal spacer 1110 may be similar in many regards to aconventional spacer.

Cross section J-J′ shows a channel for the bus bar lead. Specifically,metal spacer 1110 includes a raised portion compared to non-conductiveor insulating spacer 1105. The raised portion of metal spacer 1110effectively forms the channel or mouse hole under which the bus barleads passes to avoid electrical contact with metal spacer 1110.

One advantage of the embodiments shown in FIGS. 11A and 11B is theincorporation of a relatively wide spacer including non-conductive orinsulating spacer 1105 and metal spacer 1110. The wide spacer providesadditional area for the primary seal as compared to a conventional metalspacer. As explained above, this additional seal area, which includesprimary seal material 1140, can better protect the IGU interior frommoisture and other ambient gasses, as well as prevent argon or other gasin the interior of the IGU from escaping.

In some embodiments, non-conductive or insulating spacer 1105 includes adesiccant. In conventional IGUs, a desiccant is provided in the interiorof the metal spacer. Therefore, the metal spacer maintains its integrityin the IGU. For example, the metal spacer cannot include any holes tothe outside environment which would permit direct contact with thedesiccant when a desiccant is provided in the interior of the metalspacer. Typically, there are one or more holes used to introducedesiccant into the spacer, but these are sealed after the desiccant isintroduced.

The metal spacer may include holes to accommodate the wiring to connectthe electrochromic device bus bars with a power source. The wires can befed through the interior of the metal bus bar. These holes may be sealedaround the wires to secure the desiccant's function in the metal spacer.FIG. 11B shows an example of a diagram of an IGU in which wiring for anelectrochromic device is inside the metal spacer. As shown in FIG. 11B,IGU 1150 includes electrochromic lite 305 with bus bars 310 fabricatedon an electrochromic device (not depicted). IGU 1150 includes a two-partspacer, including an interior non-conductive or insulating spacer 1105and an exterior metal spacer 1110. Wires 1155 are in electrical contactwith leads from bus bars 310. The wires are shown as being in theinterior of metal spacer 1110 and exit from metal spacer 1110, providingelectrical communication from the interior of IGU 1150 to the exteriorof IGU 1150. FIG. 11C shows an alternative embodiment, 1160, where thewires run in the secondary seal area, external to both spacers.

In some embodiments, the non-conductive or insulating spacer and themetal spacer may form barrier between an exterior region and an interregion of the IGU. The metal spacer may include two holes, with a wirein electrical contact or communication with an electrode of anelectrochromic device passing through the first hole, though the hollowmetal spacer, and out of the second hole. The wire may provideelectrical communication from the exterior region of the IGU to theinterior region of the IGU.

The manufacturing advantage of the embodiment shown in FIG. 11B is thata spacer can be fabricated from the metal rectangular tubular portion inwhich the wires have already been fed. These metal rectangular tubularportions are normally provided as linear sections which are subsequentlybent into the rectangular shape of the spacer. If the wiring is providedin the linear sections prior to bending, the difficulty of feeding ametal wire through bent portions of the metal rectangular tubes isavoided. During manufacturing, and after the wiring is connected to thebus bar through the metal portion of the spacer, the holes in the metaltubular portion through which the wires are fed can be plugged with asealant, such as PIB, for example.

In some other embodiments, the entire spacer may be made from a materialthat is electrically non-conductive (i.e., electrically resistive orelectrically insulating) and therefore does not exhibit any of the threemodes of shorting illustrated in FIG. 4. Examples of such materials thatmay be used for a spacer include plastic materials, polymeric material,foam materials, and hard rubber materials. As an example, a foam spacersimilar to a Triseal spacer (Cambridge, Ohio), as mentioned above, maybe used. When an electrically resistive spacer is used, it may be widersuch that it occupies about 5 millimeters to about 10 millimeters of theouter edge of the IGU. This embodiment does not include a metal spacer,and the non-conductive material may be sufficiently rigid and strong toserve the role of a spacer. In some embodiments, the non-conductivespacer includes a desiccant and/or wiring, as described and illustratedin the context of FIGS. 11A-11C.

In some embodiments, a metal spacer has an electrically non-conductiveor insulating outer coating (i.e., an electrically resistive outercoating) but may otherwise be similar in design and structure to aconventional spacer. In some embodiments, the metal spacer may have asubstantially rectangular cross section. In some embodiments, thenon-conductive outer coating may be on at least one side of thesubstantially rectangular cross section of the metal spacer. In someembodiments, the non-conductive outer coating may be on all four sidesof the substantially rectangular cross section of the metal spacer. Insome embodiments, the metal spacer may include a channel configured toaccommodate an electrode of an optically switchable device on one of theglass lites.

For example, one embodiment is metal spacer coated on one or more sideswith an insulating (non-electrically conductive) coating. The insulatingcoating may be a paint or polymeric material such aspolytetrafluoroethylene or similar material. The spacer is used alongwith a primary sealant material as described herein. The spacer mayinclude a channel and/or a notch as described herein. In one embodiment,the spacer includes one or more connector keys as described herein. Inone embodiment, the spacer is coated on all sides; in anotherembodiment, the spacer is coated on only the sides proximate the bus barand/or bus bar lead.

For example, the spacer may be made from a metal having the shape anddimensions of a conventional metal spacer and be coated with anon-conductive or insulating coating. For example, the spacer may bemade from aluminum and the outer non-conductive coating may be ananodized layer. More generally, any form of passivation may be employedto provide a tough, non-conductive coating. Other metals that can beelectrolytically passivated in a similar manner to aluminum includetitanium, zinc, magnesium, tantalum, and niobium, for example. It shouldbe understood that the passivating layer also may be made from manydifferent forms of inorganic non-conductive materials, such as metaloxides, carbides, and nitrides. Alternatively, the non-conductivecoating may be an organic-based material such as a thermosetting orthermoplastic resin, a wax, an elastomer, or a polymeric material, forexample. Some examples of non-conducing-coatings include polyurethanes,acrylics, polyesters, epoxies, and hybrids of these. Painting and powdercoating are two examples of suitable processes for applyingnon-conductive organic based materials. In some embodiments, acommercially available non-conductive (e.g., insulating) paint isapplied to the surface of the metal spacer that faces the electrochromicstack. The paint may be black or clear or any other color. The paintalso may be applied to one or more of the remaining surfaces of thespacer for aesthetic reasons.

Although the foregoing embodiments have been described in some detail tofacilitate understanding, the described embodiments are to be consideredillustrative and not limiting. It will be apparent to one of ordinaryskill in the art that certain changes and modifications can be practicedwithin the scope of the appended claims.

What is claimed is:
 1. An insulated glass unit (IGU) comprising: a. a first substantially transparent substrate having an optically switchable device disposed on a surface of the first substantially transparent substrate; b. a second substantially transparent substrate; c. an electrically insulating spacer between the first and the second substantially transparent substrates, the electrically insulating spacer having a substantially rectangular cross section and comprising an electrically insulating material; d. a sealing material bonding the first and second substantially transparent substrates to the electrically insulating spacer, thereby forming a sealed interior space between the first and second substantially transparent substrates, wherein the optically switchable device faces the sealed interior space of the IGU; and e. one or more bus bars configured to deliver power to the optically switchable device, wherein the one or more bus bars are disposed, along their length, between the electrically insulating spacer and the first substantially transparent substrate, and not within the inner perimeter of the electrically insulating spacer.
 2. The IGU of claim 1, wherein the electrically insulating material is a plastic, a polymer, a foam, or a rubber.
 3. The IGU of claim 1, wherein the electrically insulating spacer contacts the first and second substantially transparent substrates along surfaces that are between about 5 mm and about 10 mm wide.
 4. The IGU of claim 1, wherein the sealing material includes polyisobutylene or polyvinyl butyral.
 5. The IGU of claim 1, further comprising wiring disposed within the electrically insulating spacer and configured for providing electrical communication between bus bars of the optical device and a power source.
 6. The IGU of claim 1, wherein the sealed interior space contains an inert gas.
 7. The IGU of claim 1, wherein the optically switchable device is an electrochromic device.
 8. The IGU of claim 1, wherein at least one of the first and second substantially transparent substrates is laminated to a reinforcing pane.
 9. An insulated glass unit (IGU) comprising: a. a first substantially transparent substrate having an optically switchable device disposed on a surface of the first substantially transparent substrate, wherein the optically switchable device is an electrochromic device; b. a second substantially transparent substrate; c. an electrically insulating spacer between the first and the second substantially transparent substrates, the electrically insulating spacer having a substantially rectangular cross section and comprising an electrically insulating material; d. a sealing material bonding the first and second substantially transparent substrates to the electrically insulating spacer, thereby forming a sealed interior space between the first and second substantially transparent substrates; and e. one or more bus bars configured to deliver power to the electrochromic device, wherein the one or more bus bars are disposed, along their length, between the electrically insulating spacer and the first substantially transparent substrate, and not within the inner perimeter of the electrically insulating spacer; and wherein the electrochromic device has a perimeter edge residing past the inner perimeter of the electrically insulating spacer, such that a portion of the electrochromic device colors under the electrically insulating spacer, the electrochromic device is configured to color completely to the inner perimeter of the electrically insulating spacer and there are no inactive area perimeter edge region scribe lines or bus bar isolating scribe lines in the electrochromic device within the inner perimeter of the electrically insulating spacer.
 10. A connector key for joining a pair of open ends of a hollow metal IGU spacer, the hollow metal IGU spacer having a substantially rectangular cross section, the connector key configured to accommodate a bus bar lead for an electrochromic device; wherein the connector key and the hollow IGU metal spacer have surfaces for mating with the glass of an IGU, which surfaces are substantially co-planar when the connector key is mated with the pair of open ends of the hollow metal IGU spacer.
 11. The connector key of claim 10, wherein the open ends of the hollow metal IGU spacer are each configured to slide over a portion of the connector key.
 12. The connector key of claim 10, wherein the open ends of the hollow metal IGU spacer are each configured to slide into a portion of the connector key.
 13. The connector key of claim 10, comprising a channel configured to accommodate the bus bar lead.
 14. The connector key of claim 13, wherein the channel is between about 0.1 mm and about 1 mm high, and between about 4.5 mm and about 10 mm wide.
 15. The connector key of claim 10, wherein the connector key is made of a metal or a plastic.
 16. An insulated glass unit (IGU) comprising: a. a first substantially transparent substrate having an electrochromic device disposed on a surface of the first substantially transparent substrate; b. a second substantially transparent substrate; c. a hollow metal spacer between the first and the second substantially transparent substrates, the hollow metal spacer having a substantially rectangular cross section; d. a connector key joining a pair of ends of the hollow metal spacer, the connector key configured to accommodate a bus bar lead for the electrochromic device; wherein the connector key and the hollow metal spacer comprise surfaces that mate with first and second substantially transparent substrates, which surfaces are substantially co-planar; and e. a sealing material bonding the first and second substantially transparent substrates to the hollow metal spacer and the connector key, thereby forming a sealed interior space between the first and second substantially transparent substrates.
 17. The IGU of claim 16, wherein the sealing material includes polyisobutylene or polyvinyl butyral.
 18. The IGU of claim 16, wherein the electrochromic device faces the sealed interior space of the IGU.
 19. The IGU of claim 16, wherein the sealed interior space contains an inert gas.
 20. The IGU of claim 16, wherein the ends of the hollow metal spacer are each configured to slide over a portion of the connector key.
 21. The IGU of claim 16, wherein the pair of ends of the hollow metal spacer are each configured to slide into a portion of the connector key.
 22. The IGU of claim 16, wherein the connector key comprises a channel configured to accommodate the bus bar lead.
 23. The IGU of claim 16, wherein the connector key is made of a plastic.
 24. The IGU of claim 16, wherein at least one of the first and second substantially transparent substrates is laminated to a reinforcing pane.
 25. An insulated glass unit (IGU) comprising: a. a first substantially transparent substrate having an electrochromic device disposed on a surface of the first substantially transparent substrate; b. a second substantially transparent substrate; c. a metal spacer between the first and second substantially transparent substrates, the metal spacer having a substantially rectangular cross section, and at least one side of the metal spacer comprising a recess configured to accommodate the length of one or more bus bars of the electrochromic device such that there is no contact between the metal spacer and the one or more bus bars, and wherein the one or more bus bars are disposed, along their length, between the metal spacer and the first substantially transparent substrate, and not within the inner perimeter of the metal spacer; and d. a sealing material bonding the first and second substantially transparent substrates to the metal spacer.
 26. The IGU of claim 25, wherein the recess is a channel.
 27. The IGU of claim 25, wherein the metal spacer is between about 10 mm and about 15 mm wide.
 28. The IGU of claim 25, wherein the metal spacer is stainless steel.
 29. The IGU of claim 25, wherein the metal spacer comprises the recess on two sides.
 30. The IGU of claim 25, wherein at least one of the first and second substantially transparent substrates is laminated to a reinforcing pane. 